Active Power Decoupling for Open-Phase Fault-Tolerant Motor Drive System Based on Third-Harmonic Injection Two-Stage Matrix Converter

For open-phase fault-tolerant motor drive system based on third-harmonic injection two-stage matrix converter (3TSMC), despite four-leg inverter and zero axis voltage compensation strategy ensure constant motor torque, there still exists double-frequency ripple power due to fault, which leads to severely input currents distortion. To solve this issue, the paper proposes a fourth-leg multiplexed buck-type active power decoupling circuit, which reuses the fourth-leg added by fault-tolerant system. By controlling decoupling circuit currents and voltage, the energy storage components absorb double-frequency ripple of motor power, the harmonic content of 3TSMC input current is greatly reduced. The simulation results verify the effectiveness of proposed topology and strategy.